Australian Sky & Telescope June/July 2018

ALTHOUGH THE AUSTRALIAN GOVERNMENT’S intention to establish a national space agency had been announced a few months ago, it was nonetheless heartening to see the initiative formalised in the 2018 federal budget in May (see page 12). With a fairly sizeable initial allocation of funds (although not as much as many had hoped), the new agency will have the resources it needs to help set a national direction for Australia’s space industry and support innovative nascent enterprises and research teams. Australia already has lots of expertise in space science and technology, and a number of very successful small space enterprises. The new agency will help stimulate even more activity and put the nation on the road to assuming its rightful place amongst spacefaring nations. At the same time, there are…

ASTRONOMERS HAVE LONG thought you couldn’t have galaxies without dark matter, just as you can’t have a cup of coffee without the cup. But the fluffy galaxy NGC 1052-DF2 contradicts this picture. Combining ground- and space-based observations, Pieter van Dokkum (Yale University) and colleagues have found that this diffuse galaxy has 400 times less dark matter compared to other systems of similar mass. In fact, it might not have any dark matter at all. The peculiar object is part of a group of galaxies 65 million light-years away that’s dominated by the beefy elliptical NGC 1052. Astronomers already knew NGC 1052-DF2 existed, but its appearance in images from the team’s Dragonfly Telephoto Array puzzled the researchers. Follow-up revealed the galaxy is so sparse that it’s see-through. Ten strangely big and…

A NEW ANALYSIS of 818 telescopic observations suggests that our first known interstellar visitor could have the shape of a flattened disk. Small-body specialist Michael Belton (Belton Space Exploration Initiatives) and colleagues pooled brightness estimates from nearly a dozen major instruments — including the Hubble Space Telescope — in order to unravel the details of 1I/‘Oumuamua’s shape and spin. Belton and co-author Karen Meech (University of Hawai‘i) say that ‘Oumuamua is tumbling, spinning every 54.48 hours with a pronounced wobble that takes 8.67 hours to complete. However, it’s unclear if the object is rotating mainly end-over-end or if the primary spin axis is close to its long axis, like a wobbling, badly thrown football. How it spins determines our understanding of its shape, which Belton’s team concludes could be anything…

NASA OFFICIALS HAVE announced that the launch of the James Webb Space Telescope will be delayed until approximately May 2020, slipping more than a year from its previous goal between March and June 2019. To date, the agency has spent $7.3 billion on Webb’s development. If the mission’s development costs go over the $8 billion maximum that Congress set in 2011, Congress will need to reauthorise the project. An independent review will nail down the changes in cost and schedule, and NASA will report its assessment to Congress in late June. This 2017 image shows all five tennis-court-size, membranous layers of Webb’s sunshield, displayed in Northrop Grumman’s clean room in Redondo Beach, California. These will have to fold into the Ariane 5 rocket fairing. The pieces of Webb are all…

Update on the aurora named STEVE For years amateur astronomers have seen and photographed a thin, faintly pink- or purple-coloured ribbon that runs east-to-west southward of the northern lights. (To read about the discovery, visit https://is.gd/aurorasteve.) Eventually dubbed ‘Steve,’ neither amateurs nor researchers knew what the phenomenon was. Analysing data from the European Space Agency’s Swarm A satellite, which flew directly through a Steve ribbon in 2016, Elizabeth MacDonald (NASA Goddard) and colleagues suggest that the amateurs had spotted the subauroral ion drift (SAID), a rapid flow of charged particles through Earth’s atmosphere that’s associated with brightening aurora. However, scientists had never known of visible emission from SAIDs, and the radiation mechanism remains unclear. In the meantime, the visual phenomenon gets to keep its name: STEVE, short for Strong Thermal…

A NEW X-RAY STUDY has uncovered a dozen potential stellar-mass black holes within 3 light-years of the supermassive black hole lurking in our galaxy’s core — and these might be just the tip of the proverbial iceberg. We’ve long known that a supermassive black hole lurks in the Milky Way’s centre. Now, a new study makes the case that up to 10,000 or so stellar-mass black holes could be keeping it company. Beginning with 16 days’ worth of observations that the Chandra X-ray Observatory had collected over the past 12 years, Charles Hailey (Columbia University) and colleagues analysed 26 sources that remain unresolved at X-ray wavelengths and lie within 3 light-years of the supermassive black hole. Typically, most X-ray emitters found near our galaxy’s centre are white dwarfs in binary…